/*
 *
 * Copyright (c) 2005 The Exceoon Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Exceoon Software Foundation (http://www.exceoon.com/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. Products derived from this software may not be called " Exceoon ",
 *    nor may " Exceoon " appear in their name, without prior written
 *    permission of the Exceoon Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * Exceoon Software Corporation and was originally based on software
 * Exceoon copyright (c) 2005, International
 * Business Machines, Inc., http://www.Exceoon.com.  For more
 * information on the Exceoon Software Foundation, please see
 * <http://www.Exceoon.com/>.
 */

package com.exceoon.equals.formula.support;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Author	David.Liu 
 * Mail		david.liu@exceoon.com
 * copyright	Exceoon corporation
 */

public class VariableContext extends ThreadLocal<Map<String, Object>>
{
	private static VariableContext context = new VariableContext();

	public static VariableContext getContext()
	{
		return context;
	}

	public List<String> getVariableNames()
	{
		return new ArrayList<String>(get().keySet());
	}

	public Object getVariable(String variableName)
	{
		return get().get(variableName);
	}

	public void addVariable(String variableName, Object variable)
	{
		get().put(variableName.toLowerCase(), variable);
	}

	public Map<String, Object> initialValue()
	{
		return new HashMap<String, Object>(10);
	}

	public void clear()
	{
		get().clear();
	}

	public boolean isVariableDefined(String variableName)
	{
		return get().containsKey(variableName);
	}

	public void addVariableDefinition(String variableName)
	{
		this.addVariable(variableName, null);
	}
}
